The Audubon Societies 121 



An illustrated lecture on this subject may be secured at any time l)y mak- 

 ing application to the undersigned. Bulletins and circular letters will be sent 

 to the boys and girls who enroll in this club work from time to time. Personal 

 visits will also be made as often as possible if desired. — Ernest K. Thomas. 



[This is a kind of work every state needs. — A. H. W.l 



V. MAKING A BIRD CENSUS 



There are various ways of making or taking a bird-census, but all depend 

 for their success upon certain rules. 



1. Define clearly the area in which the observations are taken. 



2. Study carefully the occurrrence of species in adjoining localities. 



3. Note the differences of occurrence between the foregoing and the area 

 under observation. 



4. Study reliable data of other observers, in order to avoid 'wild guesses" 

 and to eliminate errors in your own observations. 



5. Keep records in a usable form, so that data may be easily compared 

 from year to year. 



6. Distinguish between permanent residents, transients, and summer or 

 winter residents or visitors, and accidental visitors. 



7. When in doubt as to the identity of a species, never enter it in the record, 

 simply to swell the list. Continued study will enable you eventually to deter- 

 mine the most puzzling occurrences. 



8. Record carefully temperature, direction and velocity of wind, and if 

 possible, barometric pressure. 



9. Chart the area studied, designating wooded places, pastures, marshy 

 and dry places, roadside, orchards, garden, and water spaces. 



10. Study the destination and point of departure of migrating species. 



11. Learn both the common names and the scientific names of species if 

 you intend to be strictly accurate. Common names of the same species fre- 

 quently differ in different localities and are therefore liable to be misleading. 

 Scientific names are easily mastered and usually have a definite meaning, which 

 will help you to remember some distinguishing character or habit of a species. 



12. Always be open to fair criticism, and to acknowledge errors in obser- 

 vation. The most distinguished students of any subject are those who profess 

 to have the most to learn. A keen eye and quick brain are indispensable to 

 any student, and calm judgment must always precede reliable conclusions. 



A very practical illustration of how a bird-census may be taken is described 

 in Dr. C. F. Hodge's invaluable book, Nature-Study and Life. The school- 

 children of the city of Worcester, Massachusetts, worked together under Dr. 

 Hodge's direction, and made a census of the nesting-species in a city block for 

 two seasons three years apart, showing not only the number but also the 

 increase and decrease of nesting-species during that time. 



